I could suggest some more steps to get your scanner working again with Solution Center but it would be very useful to know a few more things first.
1. What is the operating system of the computer you are using (ex. Windows 7 64-bit, Windows XP, Mac OS 10.8, etc)?
2. You hint that this is connected with a USB cord, but please confirm, is this printer connected USB, wireless, or Ethernet?
3. You were able to install the software but you just cannot scan, is that correct?
4. Also, I am unable to pull up any exact documentation to assist you further as the Photosmart C4400 is the name of the series. Can you provide the model number located on the back of the printer or specify one of the many versions available (ex. C4435, C4440, C4450, etc)?
Here is a document regarding the Photosmart C4440 Scanner errors.
--An Error Has Occurred While Scanning--
It suggests checking for a firmware update. This will depend on which operating system you have but if you answer those questions for me please I will gladly help you find that information as well.